Device for producing an image of depth-dependent morphological structures of skin lesions

ABSTRACT

The present invention describes a device (10) for producing a plurality of images for assisting in characterizing skin lesions, the device comprising a capturing unit (1), in particular a video dermatoscope, for selectively illuminating and capturing recordings of an area of skin (11) presenting a skin lesion (12), the capturing unit (1) comprising magnifying optics (2) providing at least 160×, preferably at least 240×, optical magnification of the area of skin (11) for capturing morphological structures of the skin lesion (12); a focusing unit (3) associated with the magnifying optics (2) and configured to place a focal plane (F) of the magnifying optics (2) in a plurality of different depth planes (t1, . . . , tn) below a skin surface of the area of skin (11) starting from the skin surface (t0), preferably in steps; a control unit (4) configured to control the focusing unit (3) and/or the capturing unit (1) and preferably controlling them in such a manner that the capturing unit (1) captures a recording when the focal plane (F) is located in a respective depth plane (t1, . . . , tn); and a processing and output unit (5) for image production based on the image information provided by the capturing unit (1).

The invention relates to a device and a method for producing images forassisting in characterizing skin lesions of a human body.

A method known from the state of the art for capturing skin lesions,i.e., of skin changes and skin damage, is dermatoscopy orreflected-light microscopy, a non-invasive examining procedure in whichthe areas of skin to be examined are observed using a reflected-lightmicroscope under illumination with polarized light at about 10× to 20×magnification in order to identify and assess the shapes and structurestypical for certain benign and malignant types of lesions. The treatingphysician will render an assessment or a diagnosis by visualexamination. The diagnosis can be confirmed by an additionalhistological examination of the area of skin, which requires a surgicalprocedure for removing a tissue sample, however. Since the advent ofcomputer technology, individual digital images have also been producedand stored for this purpose in order to compare or evaluate them at alater time.

Likewise, it is known for a recording of the respective skin lesion tobe produced using a known video dermatoscope, for example, and todisplay it in the form of individual images in appropriate output meansfor evaluation by the respective treating physician and to store itdigitally for later comparison or analysis.

The object of the present invention is to further improve the knowndevices and methods. In particular, an optimized imaging device forcapturing and characterizing a skin lesion which enables the treatingphysician to better identify malignant and benign skin tissue is to beprovided. This object is attained by the subject matter of the dependentclaims. The dependent claims constitute advantageous embodiments of thepresent invention. Moreover, the invention addresses other issues, whichwill be discussed in more detail in the following description.

In a first aspect, the invention relates to a device for producing aplurality of images for assisting in characterizing skin lesions, thedevice comprising a capturing unit, in particular a video dermatoscope,for selectively illuminating and capturing recordings of an area of skinpresenting a skin lesion, the capturing unit comprising magnifyingoptics providing at least 160×, preferably at least 240×, opticalmagnification of the area of skin for capturing individual morphologicalstructures of the skin lesion; a focusing unit associated with themagnifying optics and configured to place a focal plane of themagnifying optics in a plurality of different depth planes below a skinsurface of the area of skin starting from the skin surface, preferablyin steps; a control unit configured to control the focusing unit and/orthe capturing unit and preferably controlling them in such a manner thatthe capturing unit captures a recording, preferably in the form of avideo or an individual image, when the focal plane is located in arespective depth plane; and a processing and output unit for imageproduction based on the image information provided by the capturingunit.

Unlike conventional dermatoscopy, the present invention makes itpossible to optically capture and subsequently produce an image of orvisualize morphological structures, in particular capillaries andcellular structures in different depth planes of a skin lesion to beexamined with the aid of the highly magnifying optics, the associatedfocusing unit, and a capturing unit connected thereto, preferably in theform of a video or digital camera, in particular a video dermatoscope.The images produced in this manner are comparable to slice images asthey are produced in histology using a microscope. Contrary to this,however, the device according to the invention makes it possible todirectly obtain color images of the morphological structures withouthaving to take tissue samples and examine them using a slide under anoptical microscope. Moreover, the present invention makes it possible toprovide color images of the morphological structures without dyeingtechniques, which are typically used in a histological examination. Thedetail images provided as video and/or individual images enable atreating physician to analyze the morphological structures of skinlesions in detail. In particular, this involves making morphological(cellular) structures visible or displaying them in different depthplanes of a skin lesion, which can be immediately evaluated by thetreating physician and offer additional diagnostic options of a lesioncompared to conventional dermatoscopy.

The magnifying optics of the capturing unit preferably allows at least160× to 400×, more preferably at least 240× to 400× and furtherpreferably at least 300× to 400×, optical magnification of the area ofskin to be examined or a lesion to be examined in the area of skin. Themagnifying optics and the associated focusing unit can be integrated ina preferably exchangeable front-end module for a camera module of thecapturing unit. The capturing unit is preferably configured as a mobileor portable handheld device.

The focusing unit can comprise manual and/or automatic adjusting meanswhich selectively vary a respective focal plane of the magnifyingoptics. The focusing unit is preferably configured to vary a distancebetween lenses of the magnifying optics and/or a distance between agroup of lenses and the camera module of the capturing unit. Theadjusting means can comprise an electric motor and/or a micro-actuator,for example. Manual or automatic adjustment can take place, for example,with the aid of a manually operable control element, such as a turningring or a rotary and/or control knob, with the aid of the control unitof the device, and/or with the aid of the processing and output unit. Auser can adjust the intended focal plane below the skin surface in theμm range.

The focusing unit is preferably configured to preferably automaticallyfocus a surface of the area of skin to be examined or of a lesion in thecourse of an initialization, such as during or shortly after beingpositioned on the lesion, in particular when the capturing unit isplaced on the area of skin presenting the lesion.

The focusing unit is preferably configured to not only focus themagnifying optics on a skin surface or a lesion surface but also toselectively place the focal plane in a depth plane of 1 μm to 50 μm,more preferably 5 μm to 50 μm, below the skin surface. In other words, adepth plane which is located 1 μm to 50 μm, more preferably 5 μm to 50μm, below a preferably initially focused skin surface is preferablyselectively focused in the process. Thus, detailed (cell) structurerecordings can be captured to a depth of up to 50 μm below the skinsurface and be displayed by the processing and output unit.Depth-dependent recordings or images of the morphological structures ofthe lesion can be captured and displayed for analysis by the treatingphysician.

The focusing unit is preferably configured to automatically or manuallyvary the focal plane in steps of 1 μm to 7 μm, preferably in steps of2.5 μm to 5 μm, in particular below the skin surface.

The control unit is preferably configured to control the focusing unitand/or the capturing unit in such a manner that an image or a recordingis captured in a respective depth plane and/or the respective image isstored.

The control unit is preferably configured to control the focusing unitand/or the capturing unit in such a manner that a predefined number ofdepth planes and/or predefined discrete depth planes are focusedselectively and/or in one sequence—preferably after an initialization ora focusing on the skin surface—and a corresponding capturing by thecapturing unit takes place. In this context, a sequence refers to aconsecutive control, preferably in a time frame of 1 to 30 seconds, morepreferably in a time frame of 1 to 15 seconds. The predefined depthplanes preferably comprise at least 2 to 20, more preferably at least 5to 15, predefined depth planes, which are preferably focused one afterthe other in steps for image capturing. For example, a control to thedepth planes at 5 μm, 20 μm, 25 μm, 30 μm below the skin surface cantake place within one predefined sequence, an image or recording beingcaptured after focusing each of these depth planes. The control unitand/or the processing and output unit can be configured to create, vary,and store predefined sequences.

The capturing unit preferably has illuminating means integrated thereinor connectable thereto, preferably a plurality of LED light sources orLED chips emitting white light in particular. The illuminating means arepreferably configured to illuminate the skin surface to be examined withpolarized light, in particular linearly polarized and/or cross-polarizedlight. The LED light sources preferably have a color temperature of 5400K to 5600 K. The color rendering index Ra of the LED light sources ispreferably at least 92, more preferably at least 95 and furtherpreferably at least 97. The illuminating means are preferably configuredto illuminate the skin surface or the lesion by reflected-lightillumination, in which the light source is disposed at a predefineddistance to the skin surface, and/or to couple light directly into theskin, in which case the illumination is provided by a light sourcedisposed directly on the skin surface. An immersion gel can be appliedto the skin surface to be examined, on which the capturing unit or afront-end module of the capturing unit is then placed, in order toreduce the refraction of light on the skin surface.

The device can comprise a positioning unit which is configured toselectively project a marking, in particular a dot or cross-line laser,onto the area of skin or onto the lesion located therein. Thepositioning unit can be disposed directly on the capturing unit or beconfigured separately therefrom. Once the magnifying optics has beenpositioned on the area of skin to be examined, the positioning unit canbe switched off.

The device preferably comprises an RGB sensor for capturing therespective image information and producing an image based thereon. TheRGB sensor is preferably comprised by a camera module of the capturingunit. The image information provided by the RGB sensor are used by theprocessing and output unit to produce images, in particular colorimages, of the respective depth plane.

The device can comprise other sensors in addition to an RGB sensor, suchas an IR sensor, a multi-spectral sensor for detecting electromagneticradiation in at least 4 to 12 predefined wavelength ranges, or ahyperspectral sensor for detecting electromagnetic radiation in at least8 to 20 predefined wavelength ranges. In this case, the processing andoutput unit is preferably configured to produce one or multiple imagesbased on the RGB, IR and/or multi-spectral or hyperspectral imageinformation. Additional illuminating means, in particular additionalinfrared or UV (LED) light sources, can be provided for capturing themulti-spectral or hyperspectral image information.

The processing and output unit of the device can be configured as acomputing unit, in particular as a personal computer (PC) or a mobiledevice, in particular as a laptop, a tablet or a smartphone, withassociated control software. The control unit can be part of thecomputing unit. The computing unit is connected to the capturing unitvia cable or wirelessly.

The processing and output unit preferably comprises at least one memoryunit and a display for displaying the captured or produced images. Forthe displaying according to the invention, the processing and outputunit preferably has a graphical interface of a software program forcontrolling the device. Moreover, the processing and output unitpreferably comprises a user interface, such as a keyboard, a mouseand/or a touch display, for controlling the processing and output unit,the control unit or an associated software program. The processing andoutput unit can additionally be connected to at least one externalserver.

Moreover, the device can comprise another capturing unit, in particularin the form of a digital photo camera, and/or another exchangeablefront-end module for the capturing unit, which is configured to capturea clinical overview image (overview image) of the patient or a referenceoverview image (reference image) of a skin lesion to be examined. Thelatter has a significantly lower optical magnification than themagnifying optics according to the invention. The term overview imagerefers to a total or partial body recording of a patient, in which atleast one or a plurality of skin lesions to be examined are depicted.The term reference image of the skin lesion to be examined refers to anindividual recording of a skin lesion, which shows the skin lesion atpreferably 10× to 25×, more preferably 15× to 20×, opticalmagnification.

In a preferred embodiment, the processing and output unit is configuredto display a respective detail image of the captured morphologicalstructures of the skin lesion, in particular a cell structure image, ina respective depth plane below the skin surface as a focused live videoimage and/or as an individual image. The detail image is preferablydisplayed in combination with a variable control element for displayingand/or adapting the respective depth plane. A user can thus use thecontrol element to preferably directly focus or select the respectivedepth plane. Furthermore, a user can take and store snapshots of a livevideo image.

The processing and output unit can be configured to provide a live videoimage mode in particular for the purpose of positioning the capturingunit. The focused surface of the area of skin or of the lesion and thecaptured image information are displayed as a live video image, i.e.,output in a display of the processing and output unit. The user can scanor trace the surface of the area of skin and position the capturing unitat the desired position for detailed analysis. Once the capturing unitis directed at the desired position, manual switching to an individualimage or frame mode can take place. Alternatively, the processing andoutput unit can be configured to detect a stationary or unchangingdirection of the capturing unit after an initial positioning and canautomatically switch to an individual image or frame mode. Therein, theindividual images can be captured in the respective depth planes.

Alternatively, a live video image of the captured image information canbe output in the respective focused depth plane as described above. Whenthe position changes in the live video image mode, snapshots taken bythe user within a depth plane can be stored, which then at leastpartially overlap and which can be joined in a coherent individual imageby the processing and output unit using a known stitching algorithm.

The processing and output unit is preferably configured to display a thedetail image of morphological structures of the skin lesion, either as alive video image or as an individual image rendering, which are capturedin a respective depth plane, in combination with a captured referenceimage of the skin lesion. The reference image depicts the skin lesionpreferably in its entirety; i.e., the respective outer contours of theindividual skin lesion are visible in the image. The combined depictionenables a user to simultaneously analyze the respective detail image andthe associated reference image of the lesion.

The processing and output unit is preferably configured to display anindicator for the respective current position of the displayed detailimage of the skin lesion in the reference image. The indicator can be aborder, such as a polygonal, in particular rectangular, marking of thecurrent position of the capturing unit in the reference image. When therespective position of the capturing unit changes, this is preferablyindicated or displayed by the indicator. The respective capturing anddisplaying of the position in the reference image can take place bymeans of a software algorithm of the processing and output unit, whichuses image evaluation to track both an initial positioning of thecapturing unit on the skin lesion and a corresponding movement of thecapturing unit relative to the skin lesion during the examination andcalculates it for a rendition in the reference image. For the respectivecapturing, additional positioning means for detecting a current positionof the capturing unit on a surface of the area of skin or of the lesioncan also be provided, which are connected to the processing and outputunit.

Furthermore, the processing and output unit is preferably configured todisplay a (clinical) overview image of a patient in combination with therespective detail image of the skin lesion and/or with a capturedreference image of the skin lesion. The overview image preferablycontains an indicator for the respective position of the depicted skinlesion in the clinical overview image. The indicator can be a border,such as a polygonal, in particular rectangular, marking of the currentposition of the lesion in the overview image.

The processing and output unit preferably comprises a processor andmemory unit (computing means), which preferably comprises acorresponding software algorithm, the processor and memory unit beingconfigured to pre-characterize and/or assess the respective captureddetail image of morphological structures of the skin lesion, preferablyusing artificial intelligence, and to output an associated informationbased thereon, preferably in the form of a risk value, and/or anidentified skin lesion class, using the processing and output unit. Thecomputing means are preferably configured to analyze the captured detailimages of morphological structures of the respective depth planes usingartificial intelligence, in particular by means of an artificial neuralnetwork trained for this purpose. The latter can in particular betrained to distinguish morphological structures of non-melanocytic andmelanocytic skin lesions. The artificial neural network can additionallybe trained to identify morphological structures of a plurality of thefollowing types of skin lesions as classes: melanocytic nevus,dermatofibroma, malignant melanoma, actinic keratosis and Bowen'sdisease, basal-cell carcinoma, seborrheic keratosis, liver spots,angioma, and/or squamous-cell carcinoma.

In a preferred embodiment, the artificial neural network is configuredto identify predefined risk classes, in particular regarding a malignityof the skin lesion. A respective risk class can reflect a respectivedegree of advancement of a skin lesion. For example, the artificialneural network can be configured to identify at least two, preferably atleast three, different degrees of advancement and therefore risk classesof a respective skin lesion which are associated with them by analyzingthe respective morphological structures. For example, they can becategorized as belonging to a low, an intermediate or a high risk class.A higher risk class can comprise degrees of advancement of skin lesionswhich are to be considered as being of higher risk to the human andwhich require timely treatment and/or surgical intervention. Furtherpreferably, the artificial neural network is configured to distinguishbetween a plurality of different degrees of advancement of a type ofskin lesion. The respective association with corresponding risk classescan be performed by the artificial neural network itself and/or by acalculation following the processing by the artificial neural network.

In a preferred embodiment, a preferably numerical risk value of therespective skin lesion is output and/or calculated based on a respectiveidentified or calculated risk class of types of skin lesions and/orbased on a respective identified degree of advancement of the skinlesion. The numerical value is preferably between 0.1 and 1. A valuebetween 0.1 and 0.2 can be defined as a low value, a value between 0.2and 0.49 can be defined as an intermediate value, and a value between0.5 and 1.0 can be defined as a high risk value.

The processing and output unit is preferably configured to display theprecharacterization and/or the assessment of the respective captureddetail image, in particular in combination with the respective referenceimage of the skin lesion. An output of the pre-characterization and/orthe assessment, such as the display of a risk class and/or a risk valueand/or an identified skin lesion class, preferably takes place in realtime or without any substantial delay, i.e., within 1 to 20 seconds,more preferably within 1 to 10 seconds.

The artificial neural network can be a known convolutional neuralnetwork (CNN). The artificial neural network preferably has at least onehidden layer, more preferably between 1 and 100, most preferably between1 and 20 hidden layers. In a preferred embodiment, the artificial neuralnetwork has between 2 and 10,000, preferably between 2 and 1000 neuronsper layer.

The artificial neural network is preferably configured to identify apredefined classification based on knowledge taught by monitoredlearning. A large number of morphological structures of skin lesions ofvarious types, different nature, and/or different progression accordingto a respective diagnosis are provided to the artificial neural network,preferably as image data, for training in a known manner by trainedlearning. They can in particular be provided from histologicalexaminations. A training of this kind can be reviewed in a known mannerin a subsequent validation process with regard to the precision ofidentification of the trained artificial neural network. Moreover, anartificial neural network already trained with a large dataset can beused and be adapted to the respective type of use with little parameterchanges by means of known transfer learning. The training and validationof the artificial neural network can take place using Python TensorFlowand/or Python Keras, for example. The image processing, the provisionand/or the association can take place using OpenCV2.4.

The artificial neural network can additionally be configured to furtherimprove previously learned knowledge in the ongoing analysis of the skinlesions from the supplied image data of the morphological structures.This means that the artificial neural network is preferablyself-learning and continuously adds to or improves its knowledge duringthe ongoing use in analyzing images of the morphological structures. Forexample, information provided by the treating physician regarding arespective diagnosis of a captured skin lesion can be taken intoaccount.

In another aspect, the invention relates to a method for producing aplurality of images for assisting in the characterization of skinlesions, preferably using a device as described above, the methodcomprising the following steps:

-   -   illuminating an area of skin to be examined by means of        illuminating means, preferably a plurality of LED chips;    -   selectively focusing an optical capturing unit with associated        magnifying optics on a plurality of different depth planes below        a skin surface starting from the skin surface, preferably in        steps, the magnifying optics allowing at least 160×, preferably        at least 240×, optical magnification of the area of skin for        capturing morphological structures of a skin lesion in the area        of skin;    -   capturing and preferably storing at least one recording of the        skin lesion in a respective depth plane by means of a capturing        unit;    -   producing at least one detail image of morphological structures        of the skin lesion based on the image information provided by        the capturing unit.

The focusing into the respective depth planes preferably takes placeautomatically and in steps at predefined intervals. The latter canpreferably be steps of 1 μm to 7 μm each, more preferably steps of 2.5μm to 5 μm each. In a preferred embodiment, predefined depth planes arefocused one after the other in one sequence, and at least one image iscaptured and stored or retained after each focusing. A respective detailimage is preferably produced and/or output by a processing and outputunit as a live image in real time, in particular in a firstinitialization, in the course of which the capturing unit is directed atthe respective desired position of the skin lesion.

During the examination of the skin lesion, a larger area can be analyzedby changing the position of the capturing unit within a respective depthplane. This results in a plurality of individual images which overlapmore or less and which can be used to calculate a coherent image in therespective depth plane by means of a known stitching algorithm. Thiscoherent image can be output on a display for analysis by a treatingphysician.

Moreover, the method can comprise the further steps of capturing a skinlesion to be examined, preferably at 10× to 20× optical magnification,and displaying a reference image of the skin lesion in combination withan associated detail image of the skin lesion, preferably next to eachother, on a display of a processing and output unit. In another step, anindicator can be additionally displayed, preferably in the referenceimage, said indicator marking a current position of the displayed detailimage in the skin lesion.

Moreover, the method can comprise other features which have beendescribed in connection with the device described above. Reference ismade to the above description of the device in order to avoidredundancies. In particular, the features described above shall also beconsidered disclosed and claimable for the method according to theinvention and vice-versa.

Other advantages, features and details of the invention are apparentfrom the following description of preferred examples of configurationsand from the drawings.

FIG. 1 is a schematic illustration of a preferred embodiment of thedevice according to the invention;

FIG. 2 is a schematic illustration of the magnifying optics and theassociated focusing unit;

FIG. 3 is a schematic side view of a preferred embodiment of thecapturing unit as a camera module with an exchangeable front-end module;

FIG. 4 is a preferred depiction of a situation in which the image of askin lesion is output according to the invention with associatedinformation.

FIG. 1 shows a preferred embodiment of device 10 according to theinvention. Device 10 comprises a capturing unit 1, which is configuredto capture a recording or an image, in particular an optically highlymagnified detail recording of morphological structures 13 a of a skinlesion 12 in an area of skin 11 of a patient P (see FIG. 4). Capturingunit 1 preferably provides digital image information or a signalrepresenting the latter based on the captured recording. Capturing unit1 preferably comprises a known video dermatoscope. Capturing unit 1 canpreferably be selectively operated in a video mode or an individualimage mode. Capturing unit 1 has a magnification option 2 and a focusingunit 3 associated with the latter and is preferably configured as amobile handheld device.

Device 10 can optionally comprise an additional capturing unit 1′. Thelatter can preferably comprise a high-resolution digital image or videocamera and is configured to capture a reference image 14 of skin lesion12 and/or a clinical overview image 16 of patient P.

Device 10 comprises a processing and output unit 5, which is connectedto capturing unit 1, 1′. Processing and output unit 5 is configured toelectronically process the provided image information or image data andto output corresponding images. For this purpose, processing and outputunit 5 comprises at least one output unit in the form of a display 5 a.The output unit can additionally be configured to provide acousticsignals or warning messages.

A control unit 4 of device 10 for controlling focusing unit 3 and/orcapturing unit 1 can be integrated in processing and output unit 5 or beprovided separately. Moreover, processing and output unit 5 comprises aprocessor and memory unit 8. The latter is preferably configured tostore and execute a software program for controlling the device.Processing and output unit 5 preferably has a user interface 9 a forcontrolling device 10 and/or a software executed thereon. User interface9 a can comprise known input means, such as a keyboard, a mouse, and/ora touchscreen.

In a preferred embodiment, processor and memory unit 8 of processing andoutput unit 5 comprises an artificial neural network, which ispreferably stored thereon and configured to identify and/or classifymorphological structures of skin lesions. The artificial neural networkcan access data stored in memory unit 8 and/or can access an externalserver or an external memory unit 30. The latter can be connected toprocessor and memory unit 8 via a communication interface 9 b ofprocessing and output unit 5. Communication interface 9 b canadditionally be configured to connect capturing unit 1, 1′ to processingand output unit 5. Communication interface 9 b can enable wirelessand/or cable communication with capturing unit 1, 1′ and/or the externalserver or an external memory unit 30.

Moreover, device 10 can comprise a positioning unit 7, which isconfigured to selectively project a marking, in particular a dot orcross-line laser, onto area of skin 11.

FIG. 2 shows a schematic illustration of magnifying optics 2 andassociated focusing unit 3. Magnifying optics 2 is configured as afront-end module 1 b for a camera module 1 a of capturing unit 1 and canpreferably be selectively connected to camera module 1 a. Magnifyingoptics 2 is configured to provide at least 160×, more preferably atleast 240×, optical magnification of area of skin 11 or of skin lesion12 so that morphological structures 13 a (see FIG. 4) can be captured indifferent depth planes of skin lesion 12. The magnifying opticspreferably comprises at least two lenses 2 a, 2 b, which are adjustablerelative to each other, and/or a lens module adjustable relative tocamera module 1 a.

Focusing unit 3 associated with magnifying optics 2 is preferablyconfigured to vary a distance between lenses 2 a, 2 b of optics 2 and/ora distance between a lens module and camera module 1 a of capturing unit1. To this end, focusing unit 3 preferably comprises adjusting means inthe form of an electric motor and/or a micro-actuator. The adjustingmeans can be controlled manually by an operator and/or automatically, inparticular by means of associated control unit 4 and/or associatedprocessing and output unit 5. As shown in FIG. 2, focusing unit 3 isconfigured not only to focus skin surface H of a skin lesion 12 to beexamined, skin surface H corresponding to a zero depth plane t₀, butalso to selectively focus a plurality of different depth planes t₁, . .. , t_(n) below skin surface H.

Focusing unit 3 is preferably configured to preferably automaticallyfocus skin surface H as a first step in the course of an initializationonce capturing unit 1 has been positioned on skin lesion 12. Focal planeF of magnifying optics 2 is placed in corresponding zero depth plane t₀(see illustration on the left in FIG. 2). Subsequently, focal plane Fcan be adjusted to depth planes t₁, . . . , t_(n) located below skinsurface H manually by a user and/or automatically by control unit 4and/or by processing and output unit 5. In the illustration on the rightin FIG. 2, for example, focal plane F is placed in a first depth planet₁ below skin surface H, i.e., said first depth plane t₁ is focused.

Predefined depth planes t₁, . . . , t_(n) can be selectively focusedindividually or one after the other in steps in a predefined sequence,wherein respective recordings or images can be captured by capturingunit 1 in each of depth planes t₁, . . . , tn.

Focusing unit 3 is preferably configured to selectively place focalplane F in a depth plane of 1 μm to 50 μm, more preferably 5 μm to 50μm, below the skin surface. Respective focal plane F can beautomatically or manually varied in steps of 1 μm to 7 μm, morepreferably in 2.5 μm to 5 μm.

FIG. 3 shows a schematic side view of a preferred embodiment ofcapturing unit 1, which comprises camera module 1 a with an exchangeablefront-end module 1 b. Capturing unit 1 preferably comprises illuminatingmeans 6, preferably a plurality LED light sources or LED chips inparticular emitting white light, which are integrated in or connectableto capturing unit 1. Illuminating means 6 preferably compriseilluminating means 6 b disposed at the end of, i.e., distally on,capturing unit 1 for coupling light directly into the area of skin 11 tobe examined. They are preferably in direct contact with skin surface Hduring the examination of area of skin 11. In order to reduce therefraction of light at the skin surface, an immersion gel can beapplied, on which capturing unit 1 is then placed. Optionally, capturingunit 1 additionally comprises reflected-light illumination means 6 a,which are disposed at a predefined distance to skin surface H.Furthermore, camera module 1 a comprises a sensor system 1 c forcapturing the recordings or image information during the examination ofilluminated lesion 12. Sensor system 1 c preferably comprises at leastone RGB sensor. Optionally, the sensor system can comprise other sensorsfor capturing image information during the examination of skin lesion 12in the different depth planes t₁, . . . , t_(n), in particular an IRsensor, a multi-spectral sensor or a hyperspectral sensor.

FIG. 4 shows a preferred illustration of a situation in which the imageof a skin lesion 12 is output according to the invention together withassociated information by means of a display 5 a of processing andoutput unit 5. The latter constitutes a graphical interface 20 on whichat least one detail image 13 of morphological structures 13 a, inparticular cellular structures and/or capillaries, in a predefined depthplane of skin lesion 12 are displayed for analysis by a treatingphysician. Detail image 13 can be displayed as a live video image or asan individual image.

Graphical interface 20 is preferably provided by a control software ofprocessing and output unit 5. Graphical interface 20 preferablycomprises patient information 18, such as a name and an age of theperson to be examined. Moreover, graphical interface 20 comprisescontrol elements 17, in particular elements for display or recordingcontrol 17 a and for selectively controlling a magnification bymagnifying optics 17 b.

In addition to detail image 13, graphical interface 20 preferablycomprises a field 21 for displaying a pre-characterization and/or anassessment of currently captured lesion 12. In particular, a risk class,a preferably numerical risk value, and/or an identified skin lesionsclass can be displayed. They can be calculated or determined based onthe evaluation of the captured recordings by means of artificialintelligence as described above.

Graphical interface 20 preferably comprises a control element 15, whichis associated with detail image 13 and serves to display and/or adaptrespective depth plane t₁, . . . , t_(n). In the latter case, a user canchange the focused depth plane of capturing unit 1 selectively andpreferably in predefined steps by shifting respective control element15. Control element 15 has a scale with predefined steps for changingthe focus in the unit “μm”, preferably from +20 μm to −50 μm. Moreover,control element 15 can comprise an adjusting function for automatic(“auto”) or manual (“fixed”) focusing.

Furthermore, graphical interface 20 comprises a reference image 14 ofskin lesion 12, which has a significantly lower optical magnificationand in which skin lesion 12 is depicted completely. Reference image 14preferably contains an indicator 14 a, which shows the current positionof detail image 13 in depicted skin lesion 12. A change in position ofcapturing unit 1 on skin lesion 12 is preferably displayed in referenceimage 14 in real time.

Moreover, graphical interface 20 can comprise another display of areference image 14′. The latter can correspond to reference image 14mentioned above but be displayed in such a manner that it can be changedby the user in terms of color rendition and/or size, for example. Forthis purpose, other reference image 14′ can comprise associated imageinformation 19, such as a magnification value.

Additionally, graphical interface 20 preferably comprises a clinicaloverview image 16 of patient P. The overview image preferably containsan indicator 16 a, which shows the respective position of displayed skinlesion 12.

REFERENCE SIGNS

-   1 capturing unit-   1 a camera module-   1 b front-end module-   1 c camera sensor system-   2 magnifying optics-   3 focusing unit-   4 control unit-   processing and output unit-   5 a display-   6 illuminating means-   6 a reflected-light illumination means-   6 b means for directly coupling in light-   7 positioning unit-   8 processor and memory unit (computing means)-   9 a user interface-   9 b communication interface-   10 device-   11 area of skin-   12 lesion-   13 detail image of morphological structures-   13 a morphological structures (cellular structures, capillaries)-   14 reference overview image (overview image)-   14 a detail image position determination indicator-   15 depth plane control element-   16 clinical overview image-   16 a lesion position determination indicator-   17 navigation and/or control elements-   17 a display/recording controller-   17 b magnification controller-   18 patient information-   19 image information-   20 graphical interface-   21 output of risk value and/or identified skin lesion class-   30 external server-   t₁, . . . , t_(n) depth planes-   t₀ zero depth plane (skin surface)-   F focal plane-   H skin surface-   P patient

1. A device (10) for producing a plurality of images for assisting incharacterizing skin lesions, the device comprising: a capturing unit (1)for selectively illuminating and capturing recordings of an area of skin(11) presenting a skin lesion (12), the capturing unit (1) comprisingmagnifying optics (2) providing at least 160× optical magnification ofthe area of skin (11) for capturing morphological structures of the skinlesion (12); a focusing unit (3) associated with the magnifying optics(2) and configured to place a focal plane (F) of the magnifying optics(2) in a plurality of different depth planes (t1, . . . , tn) below askin surface (t0) of the area of skin (11) starting from the skinsurface; a control unit (4) configured to control the focusing unit (3)or the capturing unit (1) and in such a manner that the capturing unit(1) captures a recording when the focal plane (F) is located in arespective depth plane (t1, . . . , tn); and a processing and outputunit (5) for image production based on the image information provided bythe capturing unit (1).
 2. The device according to claim 1, wherein themagnifying optics (2) allows 250× to 400× optical magnification of thearea of skin (11).
 3. The device according to claim 1, wherein thefocusing unit (3) is configured to automatically or manually place thefocal plane (F) in a depth plane (t1, . . . , tn) of 1 to 50 μm belowthe skin surface (t0).
 4. The device according to claim 1, wherein thefocusing unit (3) is configured to automatically or manually vary thefocal plane (F) in steps of 1 to 7 μm.
 5. The device according to claim1, wherein the control unit (4) is configured to control the focusingunit (3) or the capturing unit (1) in such a manner that a plurality ofpredefined depth planes (t1, . . . , tn) are focused one after the otherin one sequence and at least one recording is captured in each depthplane.
 6. The device according to claim 1, wherein the magnifying optics(2) and the associated focusing unit (3) are integrated in anexchangeable front-end module (1 b) for a camera module (1 a) of acapturing unit (1).
 7. The device according to claim 1, wherein thecapturing unit (1) comprises illuminating means (6), preferably aplurality of LED light sources, for reflected-light illumination (6 a)or direct coupling in of light (6 b) into the area of skin (2), theilluminating means (6) being integrated in or connectable to thecapturing unit (1).
 8. The device according to claim 1, wherein thedevice (10) comprises a positioning unit (7) configured to selectivelyproject a marking onto the area of skin.
 9. The device according toclaim 1, wherein the processing and output unit (5) is configured todisplay a respective detail image (13) of morphological structures ofthe skin lesion (12) in a respective depth plane (t1, . . . , tn) as alive video image or as an individual image.
 10. The device according toclaim 1, wherein the processing and output unit (5) is configured todisplay a respective detail image (13) of morphological structures ofthe skin lesion (12) in a respective depth plane (t1, . . . , tn) as alive video image or as an individual image in combination with acaptured reference image (14) of the skin lesion (12).
 11. The deviceaccording to claim 10, wherein the processing and output unit (5) isconfigured to display an indicator (14 a) for the respective currentposition of the displayed detail image (13) of the skin lesion (12) inthe reference image (14).
 12. The device according to claim 9, whereinthe processing and output unit (5) is configured to display a clinicaloverview image (16) of a patient (P) in combination with the respectivedetail image (13) of the skin lesion (12) or a captured reference image(14) of the skin lesion (12), the clinical overview image (16)containing an indicator (16 a) for the respective position of thedisplayed skin lesion (12) in the clinical overview image (16).
 13. Thedevice according to claim 1, wherein the device comprises a processorand memory unit (8) configured to pre-characterize or assess thecaptured detail image (13) of morphological structures of the area ofskin, and to output an associated information based thereon by means ofthe processing and output unit (5).
 14. A method for producing aplurality of images for assisting in characterizing skin lesions, usinga device (10) according to claim 1, the method comprising the followingsteps: illuminating an area of skin (11) to be examined by means ofilluminating means (6); selectively focusing an optical capturing unit(1) with associated magnifying optics (2) on a plurality of differentdepth planes (t1, . . . , tn) below a skin surface (H) stating from theskin surface (H), the magnifying optics (2) allowing at least 160×optical magnification of the area of skin (11) for capturingmorphological structures of a skin lesion (12) in the area of skin (11);capturing at least one recording of the skin lesion (12) in a respectivedepth plane (t1, . . . , tn) by means of a capturing unit (1); producingat least one detail image (13) of morphological structures of the skinlesion (12) based on the image information provided by the capturingunit (1).
 15. The method according to claim 14, wherein the focusinginto the respective depth planes takes place automatically and in stepsat predefined intervals.
 16. The method according to claim 14, whereinpredefined depth planes (t1, . . . , tn) are focused one after the otherin one sequence and at least one recording is captured and stored afterthe respective focusing.
 17. The method according to claim 14, wherein arespective detail image (13) is produced or output as a live image inreal time by means of a processing and output unit (5).
 18. The methodaccording to claim 14, the method comprising the following furthersteps: capturing a skin lesion (12) to be examined; and displaying areference image (14) of the skin lesion (12) in combination with anassociated detail image (13) of the skin lesion (12) on a display (5 a)of a processing and output unit (5).
 19. The method according to claim18, the method comprising the further step of displaying an indicator(14 a) for marking a current position of the displayed detail image (13)in the skin lesion (12).